Hello, and I hope I can help you today. Pregnancy with an IUD in place is rare, but just in case, you should do a urine pregnancy test. If it is positive, you need to see a GYN doctor right away for further management. If you are not pregnant, I do not know when you last checked for your IUD string or had your last exam by a GYN doctor, but if it was not very recent you should present for a pelvic examination anyway so that the doctor can make sure the IUD is still in the proper position in your uterus. You may need an ultrasound exam to help make a diagnosis. Cramping with an IUD during menstruation is common but your uterus may have pushed your IUD into an abnormal position that can cause pain, or rarely, injury to the inside of your uterus. Also a pelvic infection, a rare complication from IUDs, also can cause severe cramping. So in summary I would check a urine pregnancy test and then schedule an appointment with a GYN doctor to check your IUD and make sure it is working properly. I hope I was able to answer your question and that my advice was helpful. Best wishes, and I hope you feel better, Dr. Brown